X 7 X1 X 7 X11 0 HD
Bài 4 : Tỡm x , biết : x 7
x
1
x 7
x
11
0
HD :x
x
1
11
7 7 0
x x
1
10
x
7 1 7 0
x
x
1
10
x
x1
7 0
10
x
1 ( 7) 0
7 0 7
10( 7) 1
8
6
x
x